1. Field of the Invention
This invention relates to an image processing apparatus producing printing data, to an image forming apparatus, and a printing system.
2. Description of Related Art
Printers serving as image processing apparatuses perform printing process based on image data produced on an application program operating in a host computer as a host apparatus. One of methods for printing process has been known in which a host computer converts data to be transmitted into page description language (PDL) data or other intermediate language comparable to PDL, interpretable to a printer with the printer driver, in which the converted data is transmitted to the printer, and in which the printer expands the received data to be bitmap data to process printing based on the bitmap data (see generally, e.g., Japanese Unexamined Patent Publication No. 2005-301393).
Generally, in an image processing function owned by a printing apparatus, a PDL interpreter makes parsing processing or syntactic analysis on graphic objects described with PDL commands in the printing data, or entered data, and converts the data into a display list integrating graphic information required for the graphic objects from the parsed results. The bitmap images or the like, as data format that a printer engine mounted on the printing apparatus makes printing, are produced by a page rendering process producing a raster image (bitmap image) based on the converted display list.
Where the page description language data are transmitted to the printer from the host computer, the printer has to expand the data to, e.g., the bitmap data by processing the page description language data although a smaller amount of data makes the data transmission period shorter, and therefore, this expansion processing requires much more time, so that the printer has to operate for all processes with the system described above, so that the printing process frequently takes much time.
It is an object of the invention to provide an image processing apparatus realizing faster data processing in a case where image formation is made by transmitting data to an image forming apparatus such as, e.g., a printer. It is also another object of the invention to provide a printing system and an image forming apparatus performing communications with such an image processing apparatus.